ich9: implement SMI_LOCK

Add write mask for the smi enable register, so we can disable write
access to certain bits.  Open all bits on reset.  Disable write access
to GBL_SMI_EN when SMI_LOCK (in ich9 lpc pci config space) is set.
Write access to SMI_LOCK itself is disabled too.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c
index 18718d772e..71a9f7a716 100644
--- a/hw/isa/lpc_ich9.c
+++ b/hw/isa/lpc_ich9.c
@@ -407,12 +407,28 @@ static void ich9_lpc_rcba_update(ICH9LPCState *lpc, uint32_t rbca_old)
     }
 }
 
+/* config:GEN_PMCON* */
+static void
+ich9_lpc_pmcon_update(ICH9LPCState *lpc)
+{
+    uint16_t gen_pmcon_1 = pci_get_word(lpc->d.config + ICH9_LPC_GEN_PMCON_1);
+    uint16_t wmask;
+
+    if (gen_pmcon_1 & ICH9_LPC_GEN_PMCON_1_SMI_LOCK) {
+        wmask = pci_get_word(lpc->d.wmask + ICH9_LPC_GEN_PMCON_1);
+        wmask &= ~ICH9_LPC_GEN_PMCON_1_SMI_LOCK;
+        pci_set_word(lpc->d.wmask + ICH9_LPC_GEN_PMCON_1, wmask);
+        lpc->pm.smi_en_wmask &= ~1;
+    }
+}
+
 static int ich9_lpc_post_load(void *opaque, int version_id)
 {
     ICH9LPCState *lpc = opaque;
 
     ich9_lpc_pmbase_update(lpc);
     ich9_lpc_rcba_update(lpc, 0 /* disabled ICH9_LPC_RBCA_EN */);
+    ich9_lpc_pmcon_update(lpc);
     return 0;
 }
 
@@ -435,6 +451,9 @@ static void ich9_lpc_config_write(PCIDevice *d,
     if (ranges_overlap(addr, len, ICH9_LPC_PIRQE_ROUT, 4)) {
         pci_bus_fire_intx_routing_notifier(lpc->d.bus);
     }
+    if (ranges_overlap(addr, len, ICH9_LPC_GEN_PMCON_1, 8)) {
+        ich9_lpc_pmcon_update(lpc);
+    }
 }
 
 static void ich9_lpc_reset(DeviceState *qdev)